Divided flow, control valve system



Feb. 19, 1963 E. F. KLESSIG 3,077,901

DIVIDED FLow, CONTROL VALVE SYSTEM Filed June 27. 1960 2 Sheets-Sheet 1INVENTOR. ERNST F. KLESSIG ATTORNEYS Feb. 19, 1963 E. F. KLESSIG3,077,901

DIVIDED FLOW, CONTROL VALVE SYSTEM Filed June 27. 1960 2 Sheets-Sheet 2INVENTOR. ERNST E KLESSIG 3,077,961 DIVIDED FLOW, CUNTROL VALVE SYSTEMThis invention relates to power transmissions, and is particularlyapplicable to those of the type comprising two or more fluid pressureenergy translating devices, one of which may function as a pump andanother as a fluid motor.

The invention is more particularly concerned with a control valve systemfor controlling the operation of one or more fluid motors at will andfor automatically unloading the pump when all motors are cut out ofoperation.

One such type of control valve system which has been widely adopted as,for example in mobile road machinery applications, comprises a pluralityof directional control valves in side-by-side relationship to form whatis known as a multiple valve bank such as exemplified by the pat cuts toBer'glund, No. 2,289,567, issued July 14, 1942, and to Twyman, No.2,247,140, issued June 24, 1941. In multiple valve bank systems of thistype, a common pressure delivery or supply passage and a common returnpas-sage utilized by each valve in the bank are connectable by eachselectively operable control valve to a motor or motor ports of eachindividual valve in the bank. A by-pass or unloading passage which isinterconnected to the pressure supply passage ahead of the first valvemember also extends through the bank and remains open while all valvesare in a neutral position, the pressure delivery passage being closed toall of the motor ports of the individual directional control valve, andthus unloading the pump through the by-pass passage. When any individualvalve member is shifted to connect the pressure supply passage to amotor port of an individual valve member, the by -pass passage isclosed.

Although control valve systems of this type have proved to be adequatefor many applications, they do have some disadvantages, the main onebeing that the directional con trol valves have to be large in order tohandle the full pump displacement through the unloading passage.Although it is convenient to place in the bank as many valves as arenecessary for controlling the same number of fluid operated motors inthe hydraulic transmisison system, in some instances where it isnecessary to have a large num ber of valves in the bank, the totalpressure drop across the valve bank becomes excessive, each valve beingadded to the bank, of course, adding to the pressure drop. This can bealleviated by increasing the size of the valves, but where there are alarge number of valves in the bank, this greatly increases the size,weight, and cost of the control valve system. Also in such valvesystems, although metering may be obtained by manual manipula tion ofthe control valves, no provision has been made for providing anaccurately controlled, regulated flow from the same valve system for afluid actuated device or devices requiring a regulated flow which insome cases is substantially less than the full pump displacement, theproblem being aggravated because the pump in such systems is usuallydriven from a variable speed prime mover.

It is therefore an object of this invention to provide an improvedcontrol valve system of this general class which provides all of theadvantages of the prior art types while avoiding the disadvantages.

It is also an object of this invention to provide an improved controlvalve system for controlling a fluid operated device or devices whereinthe full capacity of the pressure fluid supply source may be utilizedfor operation of one or more of the fluid actuated devices and which3,077,901 Patented Feb. 19, 1963 is adapted to provide a regulatedamount desired quantity for the device or devices.

It is a further object of this invention provide an improved controlvalve system which is completely adequate to meet a greater variety ofhydraulic applications, which gives improved performance, and which willoperate efliciently over a long and useful life.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being bad to the accompanyingdrawings wherein a preferred form of the present invention is clearlyshown.

In the drawings:

FIGURE 1 is a sectional view of a preferred form of the presentinvention taken on line 11 of FIGURE 2.

FIGURE 2 is a sectional view of a preferred form of the presentinvention taken on line 2-2 of FIGURE 1.

FIGURE 3 is a diagrammatic view of a hydraulic power transmission systemincorporating a preferred form of the present invention.

FIGURE 4 is a partial sectional view taken from FIG- URE 1 of a modifiedform of the present invention.

Referring now to FIGURE 1, there is shown a multiple valve bankcomprising a plurality of directional control valve sections 10, 12 and14 held together by a plurality of bolts 16 in the usual manner. Thevalve section 10, which will be referred to as an inlet section, iscomprised of a housing member 13 having a longitudinal valve bore 20within which is shiftably mounted a directional control valve spool 22for controlling a double acting motor and which has a stem 23 extendingfrom the housing for manually selectively operating the same. Thehousing 18 of inlet section 10 is provided with three external connection ports shown in FIGURE 2, a pressure inlet or supply port 24 adaptedfor connection to a fluid pump, and utilization or motor ports 26 and 28adapted for connection of fluid in any operation of another fluidactuated to a double acting motor.

The valve section 12, which will be referred to as an cated by the toopposite ends of a double acting motor.

The valve section 14, which'will be referred to as an outlet section, is

comprised of a housing 40 having a longitudinal bore 42 within which isshiftably mounted a directional control valve spool type for controllinga single acting motor. It should also be understood that theintermediate section may be eliminated where two fluid. actuated devicesare to be controlled.

The pressure delivery port 24 in the inlet section is connected by aflared cored recess 52 to a pressure delivery passage 54 which extendsthrough housing 18 of said section and opens to a face thereof forregistration with the opening of a pressure delivery passage 56extending completely through the housing 50 of section 12, the openingon the opposite face of which is adapted to register with the opening ofa pressure delivery passage 58 in housing 40 of outlet section 14 andhaving a closed end therein.

Each section is provided with a check valve bore indicated by thenumeral 60, 61 and 62 spaced apart from the directional valve bore inits associated housing, the inner ends of the check valve bores 60, 61and 62 being respectively intersected by the pressure delivery passage54 in inlet section 10, pressure delivery passage 56 in intermediatesection 12, and pressure delivery passage 58 in outlet section 14. Forthe purposes of convenience, the check valves which are adapted to bemounted in the said bores have not been shown, but it should beunderstood that the check valves when mounted in bores 60, 61 and 62open upwardly to connect the check valve bore 60 to a pressure port 64of directional valve bore 20 (as shown in FIGURE 2), a pressure port 66of directional valve bore 32, and a pressure port 68 of directionalvalve bore 42. The check valve bores 60, 61 and 62 are adapted to beclosed at one end thereby by plugs, all of which are indicated by thenumerals 65.

Each directional valve bore is provided with utilization or motor ports70 and 72 on opposite sides of its associated pressure port and whichindependently lead to their respective external connection utilizationor motor ports and are also provided with return ports 74 and 76 spacedapart respectively from their utilization or motor ports 70 and 72. Tworeturn passages 78 and 80 are formed in each housing to form two commonreturn passages for the system which eventually respectively connectwith cored return passages 79 and 81 in outlet section 14, the latterpassages merging with a single return or tank passage 82 leading to thetank or return port 46. The passages 78 and 80 in each housing areconnected respectively to the valve bore return ports 74 and 76 in saidhousings.

There is also provided a common by-pass or unloading passage which isformed as follows: each valve bore of the several housing members isprovided with spaced apart by-pass ports 84 and 86, the by-pass port 86of housing 18 opening to a face of said housing to register with theopening of by-pass port 34 of housing 36 and the by-pass port 86 ofhousing 30 opening to a face thereof to register with the opening of theby-pass port 84 of housing 40. A by-pass passage 88 in the inlet sectionhousing 18 connects the inlet port 24 thereof to the by-pass port 84 ofvalue bore 20- in housing 18. As will hereinafter be explained, theby-pass port 86 of valve bore 42 in outlet section 14 is connected tothe return passage 81 beyond valve member 44 and also to a by-pass portopening to a face of the housing 40 which can be opened or closed by aremovable closure member.

Each directional control valve spool is provided with spaced apart landsfor closing either the Dy-pass port 84 or port 86 and thus closing thecommon by-pass passage. Thus the valve 22 is provided with lands 90 and92 for respectively closing the by-pass ports 84 and 86 of valve bore20; the valve spool 34 is provided with lands 91 and 93 for respectivelyclosing the bypass ports 84 and 86 associated with its valve bore 32;and the valve 44 is provided with lands 9'5 and 97 for closing theby-pass ports 84 and 86 of its associated valve bore 42. Eachdirectional control valve is biased to the neutral position shown by aspring 99 located between retainers 101 and 103.

The valve members 22 and 34 are also provided with spaced apart lands 94and 96 and the valve member 44 with a land 98. In the neutral positionof the valves shown, the pressure ports 64 and 66 of valves 22 and 34are closed by the valve land 94 of each valve member from theirrespective utilization or motor ports 70 and 72 while the pressure port68 of valve 44 is closed from its single effective utilization or motorport 72 by the land 98. When either of the valves 22 or 34 is shiftedupwardly, the land 94 of each valve which had formerly closed thepressure ports 64 and 66 to the utilization or motor ports 72 of saidvalves will now open the pressure passage and port to the utilization ormotor port 72, and the utilization or motor port 70 which had beenclosed both from the pressure port and return port will now be open tothe return port 74 of said valve member.

When the directional control valves 22 and 34 are shifted downwardlyfrom the neutral position shown, the pres sure ports 64 and 66 of saidvalves are connected to the valve utilization or motor ports 70 whileutilization or motor port 72 is connected to the return port 76 of theindividual valve member.

When valve spool 44 of section 14 is shifted upwardly, pressure port 68which had been closed to motor port 72 is now open thereto, and when thevalve spool 44 is shifted downwardly from the position shown, motor port72 which had been blocked from return port 76 is placed in communicationwith said port.

The construction and operation of the individual control valve membersand of the system so far described is well known, that is, there isprovided a multiple valve bank of the type having valve housings inside-by-side relation with common pressure delivery, return, and by-passpassages, and with individual utilization or motor ports for eachhousing. With all directional control valves in the neutral position,the common pressure delivery conduit is closed to communication with themotor or operating ports of the valve, and the by-pass passage, orunloading passage, which is interconnected to the pressure delivery passage ahead of the first valve member, remains open. Also, when any valvemember is shifted from the neutral position, the valve member shiftedcloses the by-pass passage and opens the pressure delivery passage to autilization or motor port of the shifted valve and, where a doubleacting valve is utilized, connects the remaining utilization or motorport to the common return passage.

Referring now to the improvements made in the control valve systemdescribed, means are provided for maintaining a regulated flow ratethrough the unloading or bypass passage when all valves are in theneutral position and for bypassing or shunting the remainder of thepressure fluid supply completely around the individual valve members bya separate passage connected to the return passage. For this purpose,the flared recess 52 in inlet section 10, and which is connected to thepressure delivery port 24, is not only connected to the common pressuredelivery passage 54 but also communicates with a valve bore, indicatedby the numeral 100, within. which is shiftably mounted a flow controlvalve 102 having mounted therein a pilot valve 104 for causing the flowcontrol valve to also perform the function of a main relief valve.

The flow control valve 102 is of the substantially balanced type havingtwo opposed operating surfaces indicated by the numerals 106 and 108,the former of which is exposed to pressure in the inlet recess 52 aheadof a throttle 110 in the passage 88, the latter of which connects theinlet port 24 in the inlet section to the by-pass port 84 in valvesection 10. The throttle 110 is formed in a throttling plug 111 threadedinto the passage 88. The operating surface 108 is exposed to pressurebeyond the throttle 110 by means of a passage 112 connected to passage83 and by a passage 113 connected to passage 112 and leading to thelower portion of valve bore 100. interposed in the passage 112 is arestriction 114 adapted to cooperate in the relief valve function offlow control valve 102. For this purpose the pilot valve 104 is biasedby a spring 116 to the position shown closing communi cation between apassage 120 and a passage 122 within the flow control valve, the passage122 leading directly to an isolated exhaust passage 124'. The exhaustpassage 124 extends through the housing 18 to meet with a similarisolated exhaust passage 124 extending through the housing 30 whichmeets with a similar exhaust passage 124 in housing member 44, thelatter of which is directly connected to the return passage 81 in outletsection 14.

The flow control valve 102 is biased to the position shown by a spring125 so that a land 126 of the valve blocks communication between thepressure delivery inlet recess 52 and the exhaust passage 124. Theopposed operating surfaces 106 and 168 of the flow control valve areresponsive to the differential in pressure across the throttle 110 inthe passage 83, the pressure differential being established by therating of spring 125. The flow control valve 102 operates in thewell-known manner to maintain a constant pressure drop across thethrottle 110 so that the flow through the by-pass passage will be at auniform rate. Flow in excess of the regulated amount is bypassed acrossthe land 126 of the flow control valve 102 to the exhaust passage 124,the latter of which shunts through the passage 124 all fluid in excessof the regulated rate completely around the directional control valvebores and valve members to the return passage in the last housingsection beyond the last valve member. However, when any one or more ofthe directional control valve spools are shifted to close the commonby-pass passage, a pressure differential no longer exists across thethrottle 110 in passage 88. The pressure ahead of and beyond thethrottle is equivalent to that existing in inlet recess 52, and the flowcontrol valve 102 is maintained in a closed ineffective position byspring 125. The flow control valve 102 is thus incorporated in'thesystem in a manner to maintain a regulated flow rate only through theopen by-pass passage. Fluid conducted to the pressure in to flow throughthe throttle 110 when being conducted by the inlet recess 52 to thecommon pressure delivery passage 54 when open so that the flow controlvalve is ineffective to maintain a regulated fiow rate through thecommon pressure delivery passage.

Whenever the pressure in the pressure delivery conduit reaches a maximumas determined by the rating of spring 116 of pilot valve 104, the pilotvalve 104 shifts from a seat in the passage 120 to open passage 120 topassage 122 and thus to the exhaust passage 124. Because of restriction114 in passage 112, the forces on the opposing operating surfaces 106and 108 of flow control valve 102 become completely unbalanced, andvalve 102 shifts completely to exhaust excessive pressure fluid to thereturn passage 81 in the outlet section 14 through the common isolatedexhaust passage 124.

Referring now to the outlet section 14, the housing 40 thereof isprovided with an external connection by-pass port 128 which is connectedby a passage 130 to the bypass port 86 of valve bore 42 and also to thereturn passage 81. As shown in FIGURE 1, a plate 132 is suitablyfastened to the face of housing member 40 for closing the externalconnection port opening 128. The passage 130 is threaded, as indicatedby the numeral 133, ahead of the connection of passage 130 to returnpassage 81 and beyond the connection of by-pass port 86 to passage 130,and a suitable plug may be inserted in the passage 130 as indicated bythe numeral 134 in FIGURE 4. In applications Where it is desirable notonly to operate a plurality of fluid motors utilizing the fulldisplacement of the fluid pump but in addition operate another fluid0perated device with a regulated flow, the plate be removed from theface of the housing 40 and 134 inserted in the threaded portion 133 ofpassage 130. In systems not requiring a regulated flow for the operationof a fluid operated device, the plate 132 is suitably fastened to theface external connection port serted in the passage 130.

Referring now to FIGURE 3, there is shown a hylet port 24 does not havedraulic transmission system incorporating the improved control valvesystem. There is shown a fluid pump 136 which may be of the fixeddisplacement type driven by a prime mover, not shown, and which isconnected at its inlet side by a conduit 138 to a tank 140 and connectedat the outlet side thereof by a conduit 142 to the pressure inlet port24 of section 10 of the control system. The utilization or motor ports26 and 28 of inlet section 10 are respectively connected by conduits 144and 146 to opposite ends of a double acting fluid motor 148 for drivinga load device, not shown. The utilization or motor ports 36 and 38 ofintermediate section 12 are respectively connected by conduits 151) and152 to opposite ends of another double acting fluid motor 154 fordriving another load device, not shown. The utilization or motor port 48of outlet section 14 is connected by a conduit 156 to a single actingfluid motor 158 for driving still another load device, not shown, whilethe tank or return port 46 of outlet section 14 is connected to the tank140 by a conduit 160.

For the purpose of regulating the speed of a double acting fluid motor162, a separate 4-way directional contrel valve 164 of conventional typemay be provided, the pressure delivery port 166 of which ,is connectedby a conduit 168 shown in dotted lines to theexternal connection by-passport128 of outlet section 14. Motor or utilization ports 170 and 172 ofthe directional control valve 164 are respectively connected by conduits174 and 176 to opposite ends of the double acting fluid motor 162. Aspreviously explained, when it is desired to regulate the speed of amotor such as motor 162, the plate 132 is removed from the by-pass port128 in the outlet section 114, and a plug 134 (FIGURE 4) is threadedinto the passage 130.

In the neutral position of the directional control valves shown inFIGURE 1, a portion of the displacement of the pump 136 conducted topressure inlet port 24 is conducted through the common by-pass passageof the control valve system to the passage in the outlet section, andwith plate 132 closing the by-pass port 128 and plug 134 removed frompassage 130, is connected by the return passage 81 to passage 82 andthence to the tank port 46 from whence it is conducted to the tank bymeans of conduit 160. This displacement may be regulated so as to beone-haif, one-third, or any predetermined proportion of the displacementof the pump 136. The balance of the displacement from pump 136 isconducted through the bore 101) of the flow control valve 102 and thencethrough the common exhaust passage 124 of the several housing members totank by means of exhaust passage 124 directly to the return passage 81in the outlet section from whence it is directed to the tank 140. 1

directional control valve closing the by-pass. The flow control valve102 becomes ineffective and is maintained in the closed positlon withthe by-pass passage closed. When the speed 131). The displacementthrough the by-pass passage for controlling the speed of the motor 162may be regulated by proper sizing of the throttle 110 in passage 38 andcontrolling the rating of spring 125 of the fiow control valve 102.

By use of the improved control valve system, it is possible to almostdouble the capacity of a control valve system of the same size notincorporating therein the controlled flow by-pass arrangement and toprovide a controlled flow in any predetermined quantity for theoperation of a fluid operated device. Although in the improved systemthe increased capacity does increase the pressure drop across thedirectional valves during the work cycle, this is a relatively shorttime in most mobile applications, and this is more than compensated forby the several advantages accruing. First and foremost of theseadvantages is the space saving of such improved system while anotherimportant asset is the cost saving, the savings in cost by the use ofthe flow control valve in the controlled flow by-pass part of the systemas stated being much greater than a system without the controlled flowby-pass and having the same capacity.

While the form of embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. A combined full flow and regulated flow directional control valvecomprising: a housing having a valve bore, a plurality of passagesconnected to the bore including a pressure delivery passage, at leastone utilization passage, a return passage, and a by-pass passageinterconnected to the pressure delivery passage and to the returnpassage respectively ahead of and beyond the valve bore and extending toa face of the housing; a valve member in the bore normally closing thepressure delivery passage while leaving the by-pass passage open andselectively operable to connect the pressure delivery passage to theutilization passage while closing the by-pass passage; a throttlethrough which fluid flow in the by-pass passage must pass through; aflow control valve of the by-pass type in the housing responsive to thepressure differential across the throttle for maintaining a regulatedflow rate only through the open by-pass passage; and two re movableclosure members for the by-pass passage beyond the valve bore, one ofwhich permits flow from the bypass passage to the return passage whileblocking flow to the face of the housing, and the other of which blocksflow from the by-pass passage to the return passage.

2. A combined full flow and regulated flow direction-a1 control valvecomprising: a housing having a valve bore, and a plurality of passagesconnected to the bore including a pressure delivery passage, at leastone utilization passage, a return passage, and a bypass passageinterconnected to the pressure delivery passage and to the returnpassage respectively ahead of and beyond the valve bore and extending toa face of the housing; a valve member in the bore normally closing thepressure delivery passage while leaving the by-pass passage open andselectively operable to connect the pressure delivery passage to theutilization passage while closing the by-pass passage; 2. throttlethrough which fluid flow in the by-pass passage must pass through; aflow control valve of the by-pass type in the housing responsive to thepressure differential across the throttle for maintaining a regulatedflow rate only through the open by-pass passage; a separate passageconnected to the flow control valve and to the return passage beyond thevalve bore for shunting fluid in excess of the regulated amount aroundthe valve member; and two removable closure members for the by-passpassage beyond the valve bore, one of which permits flow from theby-pass passage to the return passage While blocking flow to the face ofthe housing, and the other of which blocks flow from the bypass pass-ageto the return passage.

3. A combined full flow and regulated flow multiple directional controlvalve system comprising: means forming a housing having a plurality ofvalve bores, and a plurality of passages including a pressure supply anda return passage connected to all the valve bores, at least oneutilization passage connected to each v-alve bore, and a bypass passageconnected to all the valve bores and to the pressure supply passage andto the return passage respectively ahead of and beyond the first and thelast of said valve bores, said by-pass passage leading to and having anopening :on one face of the housing; a valve member in each boreshiftable from a neutral position for independently connecting thepressure sup-ply passage or the return passage to its associatedutilization passage, said pressure delivery passage being closed andsaid by pass passage being open with all valves in a neutral positionand said by-pass passage being closed when any valve member is shiftedto connect the pressure supply passage to an associated utilizationpassage; a throttle through which fluid flow in said by-pass passagemust pass; a flow control valve responsive to the pressure differentialacross the throttle for maintaining a regulated flow rate only throughthe open by-pass passage; a separate passage connected to the flowcontrol valve and to the return passage beyond the last valve bore forshunting fluid in excess of the regulated by-pass rate around said valvemembers; and two removable closure means, one of which closes saidby-pass passage at the face of said housing and the other of whichcloses communication between the by-pass passage and the return passage.

References Cited in the tile of this patent UNITED STATES PATENTS2,359,802 Stephens Oct. 10, 1944 2,489,435 Robinson -a Nov. 29, 19492,503,870 Harrington Apr. 11, 1950 2,607,599 Kanuch Aug. 19, 19522,710,628 Hodgson June 14, 1955

1. A COMBINED FULL FLOW AND REGULATED FLOW DIRECTIONAL CONTROL VALVECOMPRISING: A HOUSING HAVING A VALVE BORE, A PLURALITY OF PASSAGESCONNECTED TO THE BORE INCLUDING A PRESSURE DELIVERY PASSAGE, AT LEASTONE UTILIZATION PASSAGE, A RETURN PASSAGE, AND A BY-PASS PASSAGEINTERCONNECTED TO THE PRESSURE DELIVERY PASSAGE AND TO THE RETURNPASSAGE RESPECTIVELY AHEAD OF AND BEYOND THE VALVE BORE AND EXTENDING TOA FACE OF THE HOUSING; A VALVE MEMBER IN THE BORE NORMALLY CLOSING THEPRESSURE DELIVERY PASSAGE WHILE LEAVING THE BY-PASS PASSAGE OPEN ANDSELECTIVELY OPERABLE TO CONNECT THE PRESSURE DELIVERY PASSAGE TO THEUTILIZATION PASSAGE WHILE CLOSING THE BY-PASS PASSAGE; A THROTTLETHROUGH WHICH FLUID FLOW IN THE BY-PASS PASSAGE MUST PASS THROUGH; AFLOW CONTROL VALVE OF THE BY-PASS